Accurate reserve estimates are critical in the industry for proper risk assessment and providing these in a structural framework setting is unique. Traditional volumetric calculations are purely grid-based and define the volume between surfaces/horizons by computing and summarizing horizontal slices. The slicing technique does not accurately define geologic volumes especially with complex geometries such as fault blocks or salt bodies. In addition, it is challenging for the user to gain an accurate three-dimensional visual representation of the calculated volumes. Geocellular-based volume calculations also inadequately define volumes due to stair-stepped geometry representations.